first take off the tire (4 nuts)
second, take off the large nut the with cotter pin that holds the hub on the spindle, the hub wont come off yet because you have to take off the brake caliper (2 bolts) once thoes are out pull the brake caliper off the brake rotor (disk), you might have to take off the brake guard to do so,( i think 2 bolts) i just keep mine off. (the guard has lots of holes and looks like a plate)., then you can slide the hub off the spindle.
I took off the rotor when i painted mine (4 allen wrench bolts).
when i painted mine i just cleaned them really well with laquar thinner, primmed them and painted them with spray paint cans, i did 2 coats of primer and 2-3 light coats of paint and 1 coat of clearcoat.